<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        let list = [1, 5, 6, 56, 34, 5, 53, 4, 5, 5, 4]
        let liest = list.findIndex(item => item > 20)
        console.log(liest);
    </script>
</body>

</html>